Quantifying greenhouse gas emissions from municipal solid waste dumpsites in Cameroon

Open dumpsites that receive municipal solid waste are potentially significant sources of greenhouse gas (GHG) emissions into the atmosphere. There is little data available on emissions from these sources, especially in the unique climate and management of central Africa. This research aimed at quantifying CH4, N2O and CO2 emissions from two open dumpsites in Cameroon, located in Mussaka-Buea, regional headquarters of the South West Region and in Mbellewa-Bamenda, regional headquarters of the North West Region. Emissions were measured during the wet season (May 2015 and August 2016) at the Mussaka and Mbellewa dumpsites respectively. Dumpsite surfaces were partitioned into several zones for emission measurements, based on the current activity and the age of the waste. Static flux chambers were used to quantify gas emission rates thrice a day (mornings, afternoons and evenings). Average emissions were 96.80 ± 144 mg CH4 m−2 min−1, 0.20 ± 0.43 mg N2O m−2 min−1 and 224.78 ± 312 mg CO2 m−2 min−1 in the Mussaka dumpsite, and 213.44 ± 419 mg CH4 m−2 min−1, 0.15 ± 0.15 mg N2O m−2 min−1 and 1103.82 ± 1194 mg CO2 m−2 min−1 at the Mbellewa dumpsite. Emissions as high as 1784 mg CH4 m−2 min−1, 2.3 mg N2O m−2 min−1 and 5448 mg CO2 m−2 min−1 were measured from both dumpsites. Huge variations observed in emissions between the different zones on the waste surface were likely a result of the heterogeneous nature of the waste, different stages in waste decomposition and different environmental conditions within the waste. Management activities that disturb waste, such as spreading and compressing potentially increase gas emissions, while covering waste with a layer of soil potentially mitigate gas emissions. Recommendations were for dumpsites to be upgraded to sanitary landfills, and biogas production from such landfills should be exploited to reduce CH4 emissions.